A.

I would suggest removing the problem profiles, reboot and recreate just 1 new limited user profile from scratch. Try this before adding more profiles. Do not add more profiles until the problem is solved.

Then if you delete the icon cache, Windows automatically rebuilds a clean one. In Windows XP, delete the file IconCache.db found at: C:\DOCUMENTS AND SETTINGS\ USERNAME\LOCAL SETTINGS\APPLICATION DATA\IconCache.db (where USERNAME is your account name). If you do not have this file, do a search for ShellIconCache and delete it. After deleting the ShellIconCache or IconCache.db icon cache files, close all windows and choose Shut Down from the Start menu. The next time you start your computer, your icons should be fixed.

B.

Problem : Missing desktop icons for a new account
Windows keeps track of icons in user profiles. User profiles are stored in the following directory:

C:\Documents and Settings

In this folder are folder names that match the account names in Windows 2000 / XP. If you browse the folder that matches the account name that was being used before the new accounts were created, you will find a folder called 'Desktop'. In the 'Desktop' folder are the missing icons that can be copied to the new account desktop.

SAMPLE

Also, Look Here

Look Here too.